IT201900007665A1 - DEVICE FOR REBUILDING A CROSS LIGAMENT - Google Patents

Description

DESCRIPTION of the industrial invention entitled:

"Device for surgery to reconstruct a cruciate ligament"

TEXT OF THE DESCRIPTION

Field of the invention

The present invention relates to orthopedic surgery, in particular to reconstruction of cruciate ligaments.

Known technique and general technical problem

In the field of orthopedic surgery for the reconstruction of the cruciate ligaments, general use is made of surgical techniques that involve the implantation of a new ligament - to replace the native one - and its routing in a canal made artificially by bony drilling of the tibia. . In this way, an attempt is made to reproduce the arrangement and functionality of the native ligament as much as possible.

The new ligament is typically made by harvesting autologous tendons, for example semitendinosus tendon, gracilis tendon, or patellar tendon, or by harvesting donor tendons - even cadaveric ones.

In the exemplary case of anterior cruciate ligament reconstruction, a canal is made through the tibia and leads to the insertion of the native anterior cruciate ligament, then the replacement ligament is fixed at one end to the tibia, routed through the canal, and finally fixed to the femur at the opposite end. The fixing of the ends of the replacement ligament can take place either by means of terminal elements in a bush or ring that surround the end of the ligament acting as an axial stop, or with metal staples that penetrate into the bones and pinch, holding it, a corresponding end of the ligament replacement.

One of the problems inherent in these surgical techniques is the exclusively functional reconstruction of the native ligament, that is, a reconstruction that is not extended even to the accurate restoration of the anatomy. For example, the mere routing of the replacement ligament in the canal obtained by drilling the tibia does not actually reproduce the anatomical insertion of the native ligament, moreover leaving the replacement ligament exposed to interaction with the walls and extremities of the canal, a very different condition from the one found at the insertion of the native ligament.

Purpose of the invention

The object of the present invention is to overcome the previously mentioned technical problems.

In particular, the purpose of the invention is to provide a device for a surgical reconstruction of a cruciate ligament that also allows to proceed with an anatomical reconstruction of the ligament itself, in particular the insertion of the native ligament.

Summary of the invention

The object of the present invention is achieved by a device having the characteristics forming the subject of the following claims, which form an integral part of the technical teaching administered herein in relation to the invention.

Brief description of the figures

The invention will now be described with reference to the attached figures, provided purely by way of non-limiting example, in which:

- Figure 1 is an overall perspective view of a device according to the invention,

figure 2 is a longitudinal section view of the device of figure 1,

Figure 3 corresponds to the sectional view of Figure 2, but additionally illustrating the routing of a replacement (reconstruction) ligament,

- figure 4 illustrates a way of implementing the device according to the invention,

- figure 5 is a complete sectional view of the device according to the invention implemented,

- figure 6 is a detail view according to arrow VI of figure 5,

- Figure 7 is a perspective view of a tibial plate illustrating the device according to the invention laid in place,

- Figures 8A-8E summarize various embodiments of anchoring elements of the device according to the invention, and

- Figures 9A, 9B summarize various ways of manufacturing a portion of a component of the device according to the invention.

Some of figures 1 to 7 are represented, for graphic needs, with some transparent components. The connection lines of the reference numbers are indicative of the position of the component with respect to the observation point by means of their graphic coding (hatching or solid line). Figures 8A-8E and 9A, 9B include, where appropriate, a double side-by-side display corresponding to a sectional view and to the relative front view.

Detailed description

The reference number 1 in the annexed figures indicates as a whole a device for reconstruction of a cruciate ligament according to the invention. The device 1 comprises an indenter 2 and a sleeve element 4 coupled to the indenter 2. The indenter 2 defines a first passage lumen 6 while the sleeve element 4 defines a second passage lumen 8, in which the passage lumen 8 is in communication with the first passage light 6.

With reference to Figures 1, 2, the reference number 10 generally indicates a coupling interface between the indenter 2 and the sleeve element 4.

With reference to Figures 1 to 3, in a preferred embodiment the indenter 2 comprises a central annular element 12 defining the first passage lumen 6 (with relative axis X6), a peripheral annular element 14 which surrounds the central annular element 12 , and a plurality of spokes 16 which extend in a radial direction with respect to the annular element 12 and which connect the latter to the element 14.

As regards the external annular element 14, it can be made with a circular shape, or preferably with a polygonal shape, even more preferably with an irregular polygonal shape.

Furthermore, without prejudice to the polygonal shape - preferably irregular as illustrated in figures - the indenter 2 can have a constant thickness in the axial direction (axis X6), or differentiated thickness between the annular element 14 and the annular element 12, or even thickness variable - for element 14 and / or element 12 - proceeding around the X6 axis.

With this construction of the indenter 2 the coupling interface 10 is formed on the external surface of the peripheral annular element 14, and therefore extends along a plurality of segments corresponding to the sides of the polygon which defines the annular element 14. The element a sleeve 4 then takes the form of a cuff having a first end edge coupled to the indenter 2 at the interface 10, and a second end edge which defines an outlet of the second passage lumen 8.

In various embodiments, the indenter 2 can be made of a material selected from trabecular titanium, non-resorbable biocompatible materials, resorbable biocompatible materials, structured hydroxyapatite, bioglass, keratin, synthetic bone material, composite materials comprising, for example, polylactic acids or PEEK mixed with one or more of the aforementioned materials, in order to ensure mechanical properties compatible with penetration into the bone.

By way of example, in one embodiment the indenter 2 is made of a mixture of keratin-reinforced bioglasses. In other embodiments, the indenter 2 can be made, alternatively, of - PEEK and polylactic acid reinforced with hydroxyapatite or with synthetic bone,

- bio-glass reinforced with synthetic bone

- PEEK and keratin-reinforced polylactic acid. As regards the sleeve element 4, it is an element made of yielding material comprising for example bovine pericardium, connective tissue, hyaluronic acid, collagen type 1/2, silk or a mixture of different materials, for example hyaluronic acid and collagen with mesh construction.

Depending on the materials of which the indenter 2 and the sleeve 4 are made, the connection interface 10 can be made according to at least one of the following methods:

i) a seam line,

ii) a thermal or ultrasonic welding,

iii) a chemical weld

iv) a gluing.

In case i), seam line, the indenter 2 is preferably made of trabecular titanium, while the sleeve 4 is made of bovine pericardium. The indenter 2 comprises a perimeter band running along the element 14 in correspondence with which a plurality of suture holes are provided, configured to receive a suture thread which fixes the first end edge of the sleeve element 4 to the annular element 14.

In cases ii) and iii) the sleeve element 4 can be made as a collagen mesh or with a mixed composition of hyaluronic acid and collagen, while the penetrator 2 can be made of bioglass.

In this regard, as will become more evident from the following description, embodiments are particularly advantageous in which the indenter 2 is made of resorbable bio-glass, while the sleeve element 4 is made as a collagen mesh. In this case, in addition to the chemical bond between bioglass and collagen - which takes place through agglomerates of hydroxycarbonateapatite that form on the glass, generating a layer of gelatinous consistency at the interface, biological integration with the implantation site and the replacement ligament is optimal. .

In case iv), the sleeve element 4 can again - and by way of example - be made as a collagen mesh, and can be joined with a structural adhesive to a penetrator 2 made of inert bioglass.

Furthermore, again preferably it is possible to provide on the external surface of the peripheral annular element 14 and / or on the external surface of the central annular element 12, the one facing the spokes 16, one or more anchoring elements 18. With reference to Figures 8A- 8E, the anchoring elements 18 can comprise individually or in combination at least one of the following:

- quills (figure 8A),

- through holes (figure 8B),

- shearing of the wall of indenter 2 with radial protrusion (figure 8C),

- a knurling (figure 8D)

- a generic surface carving, for example obtained by increasing the roughness and / or by micro sandblasting or micro shot peening (figure 8E).

The operation of the device 1 and its implementation will now be described.

With reference to Figure 4 and Figure 6, the device 1 is configured to be introduced into a tibial plateau TP of a tibia T. In particular, the indenter 2 is shaped and dimensioned in such a way that it can penetrate stably into the tibial plateau. in an intercondylar position corresponding substantially to the natural insertion of the cruciate ligament.

For this purpose, with reference to Figures 9A, 9B, the ends of the indenter 2 opposite the coupling interface 10 and configured to first come into contact with the tibial plateau TP can be shaped in such a way as to increase the penetration capacity in the 'bone. For example, the lower edge of the annular element 14, the lower ends of the spokes 16, and the lower circular edge of the annular element 12 can be wedge-shaped (figure 9A, alternative I) or arrow-shaped (figure 9A, alternative II) to increase their bone penetration capacity, or - figure 9B - they can be made with a serrated geometry, or with a combination of the two shapes mentioned above (sawing with wedge wire, figure 9B, alternative I, or sawing with arrow wire, figure 9B, alternative II).

The installation of the device 1 requires some preliminary operations, known per se, for the preparation of the implantation site. In particular, the positioning of the device 1 is preceded by the creation of a DH canal incident on the axis of the tibia T and leading to the tibial plateau TP in a position substantially corresponding to the position of the insertion of the native cruciate ligament. The position in which the channel DH opens onto the tibial plateau TP actually provides a position reference for the device 1, which is placed on the tibial plateau TP in such a way that the first passage lumen 6 is substantially collimated with the end of the DH canal leading to the tibial plateau TP. In this way, the first passage lumen 6 is in the conditions of realizing a local extension of the DH channel.

Once the device 1 has been positioned as described above, the surgeon can proceed with its introduction into the tibial plateau TP, preferably by impulsive action such as direct percussion (with a percussion tool) or with a striking mass. In this second case, the indenter 2 can be coupled to an insertion tool which comprises a tie rod routed within the DH channel and fixed at one end to the penetrator 2. On the opposite end of the tie rod in question there is instead fixed a plate which acts from axial abutment for an annular striking mass sliding along the tie rod. Upon insertion, the surgeon will simply have to throw the striking mass against the plate, so that the binding reaction on the plate is transferred to the indenter 2, driving it into the tibial plate TP.

With reference to Figure 5, once the introduction of the indenter 2 into the tibial plateau TP has been completed, the indenter is embedded within the tibial plateau for a distance varying between 3 mm and 5 mm. Again with reference to Figure 5, in this condition - thanks to the preliminary positioning of the device 1 with the aid of the DH channel - the first passage lumen 6 creates an extension of the DH channel in order to receive a replacement cruciate ligament LC. The latter, preferably downstream of the introduction of the indenter 2 into the tibial plateau TP, is fixed to the tibia T by means of any known surgical technique (metal staples or terminal annular element), is routed within the channel DH and at the exit of this it is then routed into the first passage lumen 6 and into the second passage lumen 8. Globally, the replacement ligament LC passes through the device 1 entering from the side of the indenter 2 (passage lumen 6) and exiting the side of the sleeve element 4 ( exit of the passage light 8). The free end of the LC ligament that protrudes from the sleeve element 4 can then be fixed to a femur F, again with any known surgical technique, completing the ligament reconstruction operation.

The use of device 1 brings numerous benefits to the reconstruction operation.

Firstly, in the weeks immediately following the surgery, the device 1 offers total protection of the LC substitute ligament thanks to the fact that the sleeve element 4 wraps - protecting it - the LC ligament in a traditionally critical area such as that between the tibial plateau TP and femur F, in which - as mentioned - the LC ligament is found to be supported not by a biological insertion, but by a mechanical block and forced by the walls of the DH canal.

Secondly, but even more importantly, both the indenter 2 and the sleeve element 4 are made in a way - respectively - to favor bone regrowth and incorporation into the tibial plateau (indenter 2), and to promote fusion. with the LC replacement ligament (sleeve element 4). This means that after the reconstruction surgery a connection of the LC ligament to the TP tibial plateau is in fact recreated with characteristics similar to the natural insertion of the native cruciate ligament. The indenter 2 is indissolubly incorporated in the tibia, and the sleeve element 4 is one piece with the indenter 2 (and consequently the tibial plateau TP) and the ligament LC.

The incorporation of the indenter 2 within the tibial plateau TP is also facilitated by the anchoring elements 18 in the event that the indenter 2 is not made of resorbable material (for example hydroxyapatite, or any non-toxic and bioactive material). In this case, the creation of spikes and / or through holes allows easier penetration of the new bone tissue with the creation of undercuts that permanently retain the penetrator 2 in the bone.

If the indenter 2 is made of resorbable material, the incorporation would be even more developed. In this sense, as anticipated, embodiments are particularly advantageous in which the indenter 2 is made of resorbable bioglass, for example tricalcium phosphate, while the sleeve element 4 is made as a collagen mesh. In this case, in addition to the chemical bond between the indenter 2 and the sleeve element, the integration with the implant site (tibial plateau TP) and with the replacement ligament LC is total. Over time, the indenter 2, the material of which is non-toxic and resorbable, simply dissolves and is replaced by new bone tissue. The sleeve element 4 - as described - fuses with the replacement ligament LC, but at this point it is directly interfaced with the new bone tissue that has replaced the dissolved penetrator 2, effectively reconstructing the natural insertion of the cruciate ligament native.

In all embodiments, the penetrator 2 and / or the sleeve element 4 can be added with differentiated or undifferentiated cells, which may include chondrocytes or fibrocytes or stem cells. All these types of cells in turn can be produced in the laboratory in order to build a real tissue, and in this case they are defined as expanded. However, it is possible to use non-laboratory produced (unexpanded) cells. Furthermore, the penetrator 2 and / or the sleeve element 4 can be functionalized with or associated with proteins, growth factors or other signal molecules or target molecules, such as to further promote healing and adhesion of the sleeve element 4 to the replacement ligament LC which is introduced inside it and at the same time favoring the best integration of the penetrator 2 with the bone.

In summary, thanks to the device 1, a fusion between the LC ligament and the TP tibial plateau can be observed, at a distance from the reconstruction surgery, which benefits from conditions and properties almost identical to those of the native insertion.

Of course, the details of construction and the embodiments may be widely varied with respect to what is described and illustrated without thereby departing from the scope of the present invention, as defined by the attached claims.

Claims (10)

CLAIMS 1. Device (1) for cruciate ligament (LC) reconstruction surgery, comprising: - a penetrator (2) defining a first passage lumen (6) - a sleeve element (4) coupled to the indenter (2) and defining a second passage lumen (8), the second passage lumen (8) being in communication with the first passage lumen (6), in which: the indenter (2) is configured to be introduced into a tibial plateau (TP) and to receive a replacement cruciate ligament (LC) through said first passage lumen (6), the sleeve element (4) is configured to receive the replacement cruciate ligament (LC) through said second passage lumen (8). Device (1) according to claim 1, wherein said sleeve element (4) is made of resorbable material. 3. Device (1) according to claim 1, wherein said indenter (2) comprises at least one anchoring element (18) configured to retain the indenter (2) in the tibial plateau (TP) after introduction Device (1) according to claim 3, wherein said at least one anchoring element (18) comprises a set of quills. Device (1) according to claim 3, wherein said at least one anchoring element (18) comprises one or more openings made in said indenter (2). Device (1) according to any one of the preceding claims, wherein said indenter (2) comprises: - a central annular element (12) defining said first passage lumen (6), - a peripheral annular element (14) surrounding said central annular element (12), - a plurality of spokes (16) which extend between and connect said central annular element (12) and said peripheral annular element (14). Device (1) according to claim 6, wherein said peripheral annular element (14) has polygonal geometry. Device (1) according to claim 7, wherein said polygonal geometry is irregular. Device (1) according to any one of the preceding claims, wherein said sleeve element (4) is a hood having a first end edge coupled to said indenter (2), particularly to the peripheral annular element (14) of said indenter (2), and a second end edge defining an outlet of said second passage lumen (8). Device (1) according to claim 9, wherein said cap (4) is coupled (10) to said peripheral annular element (14) by means of one of the following: - stitching - chemical welding - thermal or ultrasonic welding - bonding.